bad wiring or bad chemistry? what's behind samsung's exploding smartphone batteries? - li ion battery cell

Samsung has had to recall thousands of Galaxy Note 7 smartphones as some of these devices are overheating and running out.
The company has not explained the reason.
This is strange because of lithium. ion batteries —
The kind used in the phone
Safe use of millions of wireless devices worldwide.
Airlines choose fire
Note 7 crashes don't happen at worse times "lithium-
Ion manufacturing is a very competitive industry . "C. -based lithium-
An ion battery consultant with a doctorate in physics.
"Manufacturers are pushing the limits of technology to a more productive product market.
So in this case, Samsung apparently tried to go too fast.
"What's wrong with Samsung? How lithium-
Lithium for lithium ion batteries
The ion battery pack placed in the sandwich became a battery.
There are a lot of changes, but all the batteries contain these core parts: the cathode: A front made of conductive materials such as aluminum.
ANode: the reverse side usually made of graphite.
Electrolyte: flammable liquid, usually made of lithium salt and organic solvent.
Separator: a thin material that separates the front and the negative, usually plastic.
To charge the battery, the current must reach the battery through a conductive material.
That's why we plug the phone into a power outlet.
Feng Saken said in an interview that when charging, lithium with positive electricity-
Ions floating in the electrolyte flow negatively from the front of the battery, flowing through the separator, which is permeable to ions.
When the battery is dead, the ions return to the positive side and wait to be charged again.
Feng Saken said that the separator can be thinner than human hair and is a physical barrier to keep both sides separate so that the battery will not be short-circuited
The circuit is overheated.
He said some areas are more vulnerable than others.
"It took quite a long time for the manufacturer to make sure there were no shorts there, but it was clear that there was a problem with Samsung's manufacturing and they had a lot of spectacular shorts," said Feng Saken . ".
Each company has its own battery formula.
"Everything is important," says Jeff Dane, a physics professor at Dalhousie University who studies lithium. ion batteries.
"This is a very complex interconnected system.
"He said that something that might be useful in a company's battery might not work in another company.
In Samsung's case, Dahnsaid said that the company may have changed the electrolyte to something that is less stable, it may increase the voltage of the battery, or it may make the separator too thin.
He said there may also be "strange interactions" between the charging method and the battery ".
"Maybe they have done this, that and so on --
There are a lot of things that could have an impact on this particular lithium.
The ion battery in this device
"This can also be attributed to testing.
Dahn said it went through "a lot of security testing" before a device went public ".
These tests have driven lithium-
"Ion batteries are hard, so I suspect people will be very surprised when this happens," he said . ".
These companies test the equipment under various conditions, but there is no test that can fully guarantee the safety of the equipment.
"Zero failure cannot be guaranteed for any test protocol.
The number zero is not scientifically credible.
The question is how big you can do it, "said GaryRubloff, a professor at the University of Maryland's Advanced Materials Processing Laboratory.
For example, Rubloff said a company could not test whether the battery would explode within 20 years.
If they do, no product will go out.
Another theory of the formation of the branch crystal is that the so-called branch crystal formation
Serious damage is known.
Rubloffsaid is a micro-fiber made of lithium.
They should not be formed in the battery, but sometimes they will also be formed.
The separator is designed to prevent these conductors from connecting the anode and cathode. A short-
Circuits can be dangerous because batteries are designed to last for a long time, so they store a lot of energy.
"If something fails, it's a big problem because you're consuming all your energy.
Stored in cells]
"Very, very fast, this can heat the battery and ignite the organic electrolyte," he said . ".
This is obviously bad for Samsung, but this problem also bothers other companies from so-
The aircraft is called a hovercraft, an electronic cigarette or even a backup power supply system.
The failure rate is small, says Dahn.
Ten years ago, there were 200 security incidents on record.
The Boeing 78 7 lithium battery makes the millions of suspended skateboards recalled in the United States safer. S.
"Today, despite the production speed of lithium
Ion may have increased by 10 times compared to 10 years ago, still 200 [
Safety Accident
A year, "he said.
Rubloff agrees that the record is good, but he says it may not matter.
"The failure rate may be small, but it doesn't matter because some of these failures can be dangerous, such as on the plane," he said . ".
Dahn said he would like to look more closely at Samsung batteries to "conduct CSI tests on them" to understand their exact chemical and structural composition.
Neither he nor Rubloff said that unless Samsung releases this information, it is impossible to know exactly what might be wrong.